Electrical safety device



ELECTRICAL SAFETY nnvxcs Find D. 6, 1968 r v INVENTORS HENRY c.HARNIS'I-LJR ANTHONY 1'. ORSELLO 3,535,667 ELECTRICAL SAFETY DEVICEHenry C. Hamish, Jr., Brantwood Terrace, Hackettstown, NJ. 07840, andAnthony J. Orsello, Elcock Ave., Boonton, NJ. 07005 Filed Dec. 6, 1968,Ser. No. 781,726 Int. Cl. H0111 85/54 US. Cl. 337-197 Claims ABSTRACT OFTHE DISCLOSURE A safety device, for household, commercial, andindustrial use, comprising an electrical intercoupling. Theintercoupling device carries an electrical socket at one end, and hasprongs extending from the other end thereof, the socket for receiving aplug-connector and the prongs for engaging a socket of a wall outlet, orthe like. Throughconnecting' strips electrically interconnect the socketand prongs, however, one of the strips, comprising a safety link, has acurrent-rated fusible section.

This invention pertains to safety devices and in particular to safetydevices useful in the household, as well as in commercial and industrialuse, and protective with respect to electrical current.

Safety devices which protect against excessive current are notorious inthe prior art, and involve fuses, circuit breakers, and the like,interposed between the external power lines and the several linecircuits, mounted in fuse boxes. Typically, one fuse or more isinterposed between the main power lines and the several line circuits,then each line circuit is separately fused. Such fusing functions wellfor the purposes involved. But it is inadequate toward inhibiting anexcessive current drain by any one electrical unit on any one line.

By way of example, a household line circuit which is fused-rated forthirty amperes of current may have a seventy-five watt table fanoperating therefrom. As the fan will demand less than one ampere ofcurrent it will have a lightand lightly insulatedline cord. Now, it isnot uncommon for a househoder to leave electrical units in unattendedoperation. Clothes dryers, freezer units, etc., are commonly inoperation out of sight of the householder. Not infrequently, in summerseason for instance, it can be expected that the house may be absentedfor hours while the table fan, let us say, is left operating. Now,should the fan become defective, developing a short circuit perhaps, itsseventy-five watt load will thereby be shunted. The short circuit willpass more and more current-at least up to the thirty amperes availablethrough the remote fuse box thirty ampere fuseuntil, hopefully, thelatter fuse opens the line circuit.

Before the basement thirty-amperes fuse opens, the light line cord ofthe fan may well be a charred ruin. All too frequently, however, theoverheated line cord will flame, and the house will become anotherstatistic of the National Fire Protection Association. It is thisAssociation which advises that fire damage to American homes runs toover three hundred millions of dollars each year; on the basis ofnational averages, one home in every neighborhood, each year, will havea fire, and every day seventeen peoplemostly the young and ageddie inthese fires.

Clearly, what is needed then is a more facile safety device protective,certainly, of the home, and of commercial and industrial establishmentsalso, against the lethal albeit useful flow of electrical current.

It is an object of our invention, therefore, to teach a safety devicefor household and general use especially configured for interpositioningbetween the using elec- United States Patent 0 3,535,667 Patented Oct.20, 1970 trical unit and the fuse box fuse for the line circuit.

Especially is it an object of our invention to teach a safety device ofthe type noted having means automatically operative for interrupting afiow of electrical energy upon said flow exceeding a predetermined rate.

A feature of our invention comprises the provisioning of anintercoupling device for electrically connecting between electricalconnectorssuch as a plug and a socketsaid device having a safety linkwith a current-rated fusible section therein.

Further objects and features of our invention will become more apparent,by reference to the following description taken in conjunction with theaccompanying figures, in which:

FIG. 1 is a side elevation view, partly in section, depicting thedeployment of an electrical line circuit in a household, according tothe practices of the prior art;

FIG. 2 is a side elevational view, partly in section, of the safetydevice according to our invention, in one embodiment thereof;

FIG. 3 is an end view of the safety device of FIG. 2, looking along theprongs extending therefrom and towar the housing thereof;

FIG. 4 is a side elevational view, partly in section, of an alternateembodiment of the invention; and

FIG. 5 is an end View of the safety device of FIG. 4, partly in section,looking along the prongs thereof toward the housing.

As shown in FIG. 1, a part of a house 10, including a living room 12 anda kitchen 14, has a line circuit 16 in service thereof. Line circuit 16proceeds from fuse box 18 situated in the basement, lbeing fused by afuse 20. The fuse box 18 receives power lines 22 therewithin.

Line circuit 16, through fuse 20, supplies electrical current to outlets24,26, 28 and 30, which power a number of electrical units. Thus, outlet24 powers an electrical clock 32 rated at seventy-five watts, and astanding lamp 34 rated at three hundred watts. Outlet 26 provides powerfor television set 36, and outlet 28 supplies toaster 38. Outlet 30supplies current for a range lamp 40, and the line circuit 16 furtherprovides power to an exhaust fan 42.

Typical wattage ratings for units such as the television set 36, toaster38, range lamp 40, and the exhaust fan 42, are, by way of example, 300watts, 1100 watts, 60 watts, and 60 watts respectively. The wattagerating for line circuit 16, then, would dictate its fusing, at fuse box18, for twenty amperes.

Now, consider, there is no unit on line circuit 16 which might be leftoperative and unattended excepting perhaps lamp 34 or electrical clock32. Actually, the very nature of electrical clocks mandates theircontinuous operation. Therefore, in both the presence and absence of thehouseholders, clock 32 will be continuously operative. Should clock 32develop a direct short circuit, its normal demand of current of lessthan one ampere will not save the situation. The clock motor, theseventy-five watt load, will be shunted by the short circuit, and clock32 will pass up to twenty amperes of current therethrough. Before theline circuit fuse 20 in fuse box 18 opens, the line cord of clock 32will overheat, smoke, perhaps flame. Adjacent curtains, if any, couldflame. Outlet 24 likely will overheat, and the wires of circuit 16,which convey current to outlet 24 also are subject to overheating,charring, and flaming. It is the avoidance of this everpresent hazardwhich the teaching of our invention provides.

If the line cord of clock 32, and the outlet 24 had a safety linkconnector interposed therebetween, especially such a connector havingmeans automatically operative for interrupting a flow of electricalenergy therethrough upon said flow exceeding a predetermined rate offlow,

then inordinate current conduction can be positively interdicted.

The device 44 of our invention, shown in FIG. 2, provides for thissafety interdiction.

Device 44 comprises a housing 46 which mounts at one end thereof aplurality of sockets 48. Sockets 48, as FIG. 2 illustrates, are recessedin housing 46 therein to receive the mating prongs of an electricalplug. Sockets 48 constitute that which is customarily identified as afemale connector. At the other end of housing 46 are supported therein,and extendibly therefrom, prongs 50. Only one prong 50 is visible inFIG. 2 as the other thereof is directly behind the one shownthe twobeing supported in parallel. A connector strip 52 electricallyinterconnects one of said sockets 48, the latter being of the customarymetal sleeve type, with one of said prongs 50, and said prongs being ofthe customary knifetype known as male connectors. A safety linkconnector strip 54 electrically interconnects the other of said sockets48 with the other of said prongs 50. As seen in FIG. 3, strip 54 has aconstricted portion which comprises a fusible section 56. Fusiblesection 56 will open and separate the respective ends of safety linkstrip 54 upon the conduction therethrough of excessive current.

Device 44 can be configured for the current-rating warranted by anygiven diversity of electrical units. Thus, where in a household, forinstance, a continuously-used electric clock is current-connected to anelectrical source-as at outlet 24, as shown in FIG. la oneampere-rateddevice 44 would be used. The line cord of clock 32 would have the plugconnector at the end thereof engaged with sockets 48 of our device 44,and prongs 50 of our device, would be inserted into outlet 24. Then,upon clock 32 short circuiting, the line cord therefor, and line circuit16 as well, will never pass the potentiallylethal and otherwise whollyavailable twenty amperes of current. When a short circuit in clock 32passes only a first ampere of current, fusible section 56 Will melt andopen. Thus, only the clock-serving branch of line circuit. 16 will beinterrupted. Outlets 26, 28, and 38 will still be operative, and serviceto exhaust fan 42 will continue. Finally, it is to be noted that thesecond section, i.e., the lower section (as shown in FIG. 1) of outlet24 is stilloperative for service. Especially it is to be noted that nofuse in fuse box 18 needs replacement; the fuse 20, for line circuit 16,will not have opened.

A television set having a three hundred watt rating would have a fourorfive-ampere device 44 constantly interposed between the plug-connectortherefor and the outlet to which it always connected. A one thousandwatt electric iron would be throughconnected with the electrical sourcetherefor through an eleven or twelve ampere device 44.

Our invention, then, is not limited to a safety device 44 of any givenampere rating. Our invention contemplates a broad spectrum of devices 44having fusible sections of varied fusible capacities.

With the use of our device 44, at critical or all electrical outlets andconnections, a household may be absented for hours, for weekends, forseveral weeksfor vacations and the like-with one or more electricalunits continuously operative, without risk of fire to the house.

The frequency with which a basement-located, or otherwise remotelylocated line circuit fuse needs replacement is markedly reduced, perhapseliminated, depending upon the universality with which our devices 44are deployed throughout the household.

House line circuits, such as those of line circuit 16 of FIG. 1, neverhave any one unit; iron, toaster, clothes dryer, or whatever, poweredthereby which unit requires all the current for which the line circuieis rated and holds available. That is to say, a line circuit rated forfifteen amperes will have as its greatest single loading hundred wattappliance, such as a television set for instance. A line circuit ratedfor twenty amperes will likely number among the units it serves afourteen hundred watt rotisserie or a sixteen hundred watt hot plate.Therefore, it is latently dangerous, an ever-present invitation todisaster, to ill-protect the lightly insulated, lowcurrent units andappliances, which are carried on the same line with some heavy-loadingunits, against short circuiting which can cause minor or majorconflagrations. To put it bluntly, a simple, three-dollanvalue,sixty-watt bed lamp short circuiting a twenty-ampere line could reduce athirty-thousand-dollar home to ashes. Tragically, it happens. Everyminute of the day an American home is destroyed or damaged by firesaysthe National Fire Protection Association.

Our device 44 is of inordinately simple construction. Housing 46 is ofnon-combustible, flameand heatresistant plastic composition, and sockets48, strips 52 and 54, together with prongs 50, need only be supported ina plastic mold until housing 46 formed therein firms up. It iscontemplated that prongs 50 would be supported above a mold, suspendingstrips 52 and 54 and sockets 48 connected thereto within the mold, untilthe plastic composition solidified. But the manner of construction isnot the subject of this invention; any one of several methods offabrication will occur to those skilled in the art to which ourinvention pertains. Our invention comprises the overall device 44,however derived, a simply-formed device of inexpensive manufacture whichmarkedly inhibits the risk of home, commercial, and industrial firethrough electrical failures.

As it is now, in the prior art, a fuse box fuse will blow, cutting allpower to a line circuit, or cutting all power to the home, commercialestablishment, or Whatever. With this occurrence it is now known,initially, whether the fuse failure proceeded from an overloaded linecircuit or a short circuit in some one unit. Should the latter be thecase, often it is not readily to be determined Which one unit shortedout. Overheating and charring may have occurred behind the walls, withlittle or no visually discernible evidence of overheating in any givenunit. Of course, replacing the fuse does not solve the problem; this butre-introduces the fire risk. Yet, power must be re-introduced before itcan be determined which using unit shorted out and is no longeroperative. If the faulty unit is an iron, television set, or the like,one will have to wait for a considerable lapse of time to be certainthat the suspect unit is not heating upand will not heat up. And duringthis lapse of time, wallconfined line circuit wires can be cookingagain-until the replacement fuse blows, or the defective unit isidentified. Our device 44 completely avoids this problem. Where allunits on a line circuit are safeguarded by our devices 44, any one unitthereon which fails to operate, after any lapse of time, is readilyidentified as the defect1ve unit; all other units continue to operate.Further, our devices 44 insure that, whatever the lapse of time, thewall-confined line circuit wires will never carry the wholly availabletwentyor thirty-ampere current therethrough.

In FIGS. 4 and 5 we teach an alternate embodiment of our device which isusable with the well-known grounded plug and outlet. This embodimentteaches a safety device 58 which has a ground connection provisionedtherein. A female-type ground socket 60 is provisioned, and a groundprong 62, the two being conductlvely interconnected by means of aconnector strip 64. Prongs 50, being identical with those of the FIGS. 2and 3 embodiment, are provisioned for engagement with the electricaloutlet, and sockets 48 again, with connector strips 52' and 54'electrically interconnecting therebe tween. The safety link connectorstrip 54 has a fusible section 56' therein, shown in FIG. 4, whichopenslike section 56 of the FIG. 3 embodiment-when the current passingtherethrough exceeds the current rating for which the section isdesigned.

In both the embodiments, device 44 and device 58, we teach the use ofconnector strips 52 and 52', and safety link connector strips 54 and 54,the latter having constricted fusible sections 56 and 56', respectively.This is only exemplary of our invention. Connector rods could be used aswell, in lieu of strips, the rods having fusible sections characterizedby reduced diameters.

Accordingly, while we have described our invention in connection withspecific embodiments thereof, it is to be clearly understood that thisis done only by way of example and not as a limitation to the scope ofour invention as set forth in the objects thereof and in theaccompanying claims.

We claim:

1. A safety device, comprising:

a housing;

first means for mechanically intercoupling a plurality of electricalconnectors;

said first means including at least a pair of electricallyconductivesockets disposed in parallel and embedded in said housing in a givenlongitudinal orientation, and at least a pair of electrically-conductiveprongs disposed in parallel and partially embedded in said housing andpartially extending therefrom in a position rotated at least 90 degreesof arc from said given longitudinal orientation; and

second means for conducting a given, predetermined rate of flow ofelectrical energy from at least one connector of said plurality to atleast another connector of said plurality;

said second means including at least a pair of electrically-conductivestrips irreplaceably sealed within said housing, each of said stripsproviding for electrical conductivity between one socket of said pairthereof with one prong of said pair thereof, each of said strips beingconnected to one socket and one prong, and at least one of said stripsincludes a fusible section automatically operative for interrupting saidenergy flow upon said flow exceeding said predetermined rate.

2. The invention, according to claim 1, wherein:

one of said strips lies in a given plane;

another of said strips lies in a different plane which transverses saidgiven plane; and

a further one of said strips lies in a plane which transverses both saidgiven and different planes.

3. The invention, according to claim 1, wherein:

said housing has flat, oppositely disposed ends;

one end of each of said sockets opens on one of said flat ends, saidsockets extending longitudinally into said housing more than half thedistance subsisting between said flat ends disposing the other ends ofsaid sockets in near adjacency to the other of said fiat ends; 7

said prongs have terminal ends within said housing,

said terminal ends being disposed substantially midway between said fiatends; and

said strips are connected to said terminal ends of Said prongs and saidother ends of said sockets.

4. The invention, according to claim 1, wherein: said first meanscomprises three electrically-conductive sockets, and threeelectrically-conductive prongs; said second means comprises threeelectrically-conductive strips; and

one of said sockets, prongs, and strips comprise a groundingthroughconnection. 5. The invention, according to claim 4, wherein: saidstrips lie in parallel planes.

References Cited BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN,Assistant Examiner US. Cl. X.R. 337 269

